Introduction
This information aims to answer some of the questions you may have about leech therapy. It explains the benefits, risks and alternatives of the procedure, as well as what to expect.
If you have any questions or concerns, please do not hesitate to speak to one of the team caring for you.
What are leeches and why are they used?
Medicinal leeches are worms that suck and feed on blood. Their scientific name is Hirudo medicinalis and Hirudo verbana.
They have been used in medicine since the dawn of civilization, and recently there has been an increase in using leeches in reconstructive surgery.
Leeches help to improve blood circulation in congested flaps or other tissue (such as an amputated finger that has been re-attached).
How do they work?
They latch to the skin with their tiny sharp teeth and their saliva contains a number of chemicals to aid them to suck and feed on blood. These chemicals include a local anaesthetic (to reduce pain) and blood thinners.
Am I going to feel pain?
Leech bites are typically painless because they have a local anaesthetic in their saliva.
What are the benefits of leeches?
In some cases where blood is congested and needs to be released release, leech therapy can help.
Leeches can suck a large amount of blood relative to their body. Each leech can suck between 5 - 15 millilitres of blood in one feed. The bite mark can still bleed a little for up to 72 hours after the leech has detached, due to the blood thinners in the leech’s saliva which act only locally (on this area). This often resolves the problem with the circulation.
Why was I chosen to be offered leech therapy?
You have been offered leech therapy because we believe it would be the best treatment for your congested flap or other tissue.
If there is not enough outflow of blood in this area and it is left untreated, it may lead to the flap or other tissue dying.
What are the side effects and risks of leeches?
- Leech therapy is often associated with bleeding and commonly transfusion of blood / blood products during or after treatment. We will do blood tests every day to see if you need a blood transfusion. Leech therapy will not be started unless you are comfortable with the possibility of blood transfusion. If you cannot or would not like to have blood transfusion, leech therapy will not be started.
- Leeches contain bacteria that sometimes cause infection. You will be started on an oral antibiotic to prevent this. The leech site will be monitored daily by the nurses and doctors. If you are allergic to any of the antibiotics started, please tell your medical team and you will be offered an alternative antibiotic.
- Rarely, people may develop an allergic reaction to leeches. Leeches will not be used on you if you have any history of allergic reactions to them.
- Leech therapy may not be suitable if you have an immunodeficiency, bleeding disorders, heart problems, unless you and your consultant decide the benefits of using leeches outweighs the risks.
- eeches can sometimes migrate into dressings. Nurses will be closely looking after your leeches when they are used.
- It has been reported that some patients may have some psychological difficulties in dealing with leeches. If that is the case, our psychologists will be happy to offer their advice and help.
- Leeches in our department are never used between patients and are disposed of humanely and safely. Transmission of blood borne diseases is not a risk.
Is there an alternative?
Usually, if your doctor has decided to use leech therapy, it means it is the last resort to save your congested flap. If you choose to do nothing, blood may clot and prevent blood flow to the flap. This may lead to some or all the tissue dying and the flap will need to be removed.
How do I give my consent?
If you agree to go ahead with leech therapy, you will be asked to sign a consent form.
What happens next?
- The nurse will clean the area and apply the leech. Sometimes the nurse will scratch the area to allow the leech to latch on.
- We will closely monitor the leeches and the area to check its response to treatment. The number of leeches used and how often we use them depends on the response.
- You will have daily blood tests.
- After each feed, leeches are disposed of safely and according to trust policy.
What do I need to do?
You will be asked to stay in a position that allows the leech therapy to work.
You will be asked to avoid eating or drinking any caffeine- containing food or drinks (such as tea; coffee or cola) and to avoid the use of nicotine-containing products (such as cigarettes or nicotine replacement therapy), during your hospital stay.
What do I need to be aware of after the leech therapy finishes?
There are no specific aftercare instructions. However, if you feel unwell (for example, if you have a fever, increased redness, or pain in the area) please let the team caring for you know.
Contact us
If you have any questions or concerns about leech therapy, please talk to your clinical team, including your plastic surgeon, plastic clinical nurse specialist, nursing team or pharmacy staff.
You can also speak to the ward sister or nurse in charge of Ward 33A on 0117 414 3100.
Feedback
If you would like to give us any feedback on your care or treatment please see this page Feedback | North Bristol NHS Trust
Further information
- For online information about health visit nhs.uk
- NHS 111 offers medical help and advice from fully trained advisers supported by experienced nurses and paramedics. Available over the phone 24 hours a day.
- References available on request.
© North Bristol NHS Trust. This edition published June 2026. Review due June 2029. NBT002763